It's kind of a fight between Lucifer Sam and Scarecrow for me. But since I've had Lucifer stuck in my head literally all last week, I just went with that siame cat! Not that I was struggling to get that song out of my head. It's catchy bassline is the tops.
bike is horrendus, (spl), it has no interesting qualities to me at all.
Gotta be Bike..... 
I love Scarecrow. It's one of my all-time favorite Pink Floyd songs.
As cliche as it is, I have to go with Bike. I'm not that crazy about Piper in general, but Bike is just such a great song.
Flaming, with Lucifer Sam as a close second!
Chapter 24. I don't know why I just like it for some reason unknown to me.